Re: [Qemu-devel] [SeaBIOS] [PATCH RFC 00/13] qemu: generate acpi tables for the guest

[Gerd Hoffmann <kraxel@redhat.com>]

  Hi,

> Actually, this is a very good example.  In more modern boxes like Flex,
> there's a PCI-Express backplane that all of the nodes are connected to
> with a common set of slots for all nodes.  You can configure in firmware
> how the slots map to each node.

Well, we don't configure the dynamic things we have today (s3/s4 enable,
numa nodes, pci hotplug, ...) using some firmware setup utility, but
using qemu command line switches.

So we have no reason to generate acpi tables in the firmware, we can
equally well do it in qemu.

The advantages of doing it in qemu:

  (1) We don't have to create/extend fw_cfg interfaces to pass all
      sorts of config info.
  (2) It decouples qemu and seabios; we don't have to touch seabios for
      every new feature which needs something acpi-ish.  For example we
      could have done pvpanic support without touching seabios.
  (3) We don't have to duplicate the logic which compiles acpi tables
      from fw_cfg in seabios & ovmf.

The advantages of doing it in seabios:

  (*) Your list here, I don't see any.

cheers,
  Gerd